In the past, in the process of producing an alloy containing Mg, the general practice had been to add Be.
Be, when added in a small amount, enables inhibition of oxidation loss of the Mg-containing alloy melt and has frequently been used to prevent burning of highly reactive Mg alloy melts and various other alloy melts containing Mg.
However, the problem of health effects has been pointed out for Be. Recently, means for avoiding its use have been searched for.
On the other hand, the method of adding Ca as an alternative to Be addition and cover flux is known (Muromachi, Shigeo and Minegishi, Tomohiro, “Effect of Ca on Al—Mg Alloys”, KEIKINZOKU, vol. 10, no. 6, (1960): pp. 25 to 28).
Further, in Japanese Patent Publication (A) No. 2001-64743, addition of Sr has been demonstrated to have an effect that reduces surface oxidation on a slab. However, it is unclear as to whether there is an effect in inhibiting oxidation loss when in a high temperature melted state.
That is, in practice, only Ca has been demonstrated to be an alternative to Be.